A Study to Learn About a Clostridioides Difficile Vaccine in People 65 Years of Age and Older
Trial statusRecruiting
Trial phasePhase 3
Trial typeInterventional
Biological sexAll
Age65+
SponsorPfizer
About this trial
The purpose of the study is to learn about how effective, safe, and tolerable the Clostridioides difficile (C. difficile) vaccine is in decreasing the number of C. difficile infections (pCDI) in adults 65 years of age or older.
The participants will receive either the C. difficile vaccine or placebo (saline). A placebo does not contain any active ingredients. The vaccines will be given as a shot into the upper arm muscle.
This study looks at the number of diarrhea (loose stools) events related to a C. difficile infection, so the length of the study can change. If these events happen quickly, the study may finish sooner; if they happen slowly, it could take longer. Sometimes, the study might stop early if the vaccine clearly does not work. Participants will stay in the study until enough events have occurred to answer the main question. On average, each person is expected to take part for up to about three and a half years.
During this time, participants will have 3 planned clinic visits and 3 planned phone visits. After these visits, more scheduled clinic visits will happen every year until the end of study.
Besides the scheduled study visits, if at any time during the study a participant has 3 or more loose stools in 24 hours, they will be asked to save the next one (the fourth or later) and contact the study site. The study site will check to see if it could be a C. difficile infection. This check may happen at the clinic or through a phone or video call.
Eligibility criteria
This trial accepts healthy volunteersQualifiers
None
Disqualifiers
Anyone who has had CDI before.
Anyone who has had surgery to remove part of their small or large intestine.
Anyone who often has diarrhea (meaning three or more loose stools in a day, more than once a month).
Anyone who has already received a vaccine or special antibody treatment for C. difficile.
Trial design
Design model
Parallel
Treatments tested in this trial
C.difficile vaccine
Biological/VaccineC.difficile vaccine given as an intramuscular injection
Saline Placebo
Other intervention0.9% sodium chloride solution given as a intramuscular injection
Treatment groups
32,500 Participants
are divided into 2 treatment groupsGroup A: C.difficile vaccineExperimental treatment 1 intervention
Group B: Saline PlaceboOther 1 intervention
Trial outcomes
Primary outcomes
1
The percentage of participants reporting local reactions
Injection site pain, redness, and swelling as self-reported in electronic diaries
Time frame
For 7 days after each vaccination2
The percentage of participants reporting systemic events
Fever, vomiting, fatigue, headache, muscle pain, and joint pain as self-reported in electronic diaries
Time frame
For 7 days after each vaccination3
Percentage of participants reporting adverse events
As elicited by investigator site staff
Time frame
From each vaccination through 1 month after each vaccination4
Percentage of participants reporting serious adverse events
As elicited by investigator site staff
Time frame
From Vaccination 1 (Day 1) through 12 months after Vaccination 2 (last dose) (18 months)Secondary outcomes
1
The incidence of antibiotic use in the treatment of a first episode of the primary CDI
First episode of primary CDI with antibiotic use incidence per 1000 person- years of follow- up
Time frame
from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)2
The incidence of severe or fulminant primary CDI
First episode of severe or fulminant primary CDI incidence per 1000 person- years of follow- up
Time frame
from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)3
The incidence of a first episode of primary CDI (any severity)
First episode of primary CDI incidence per 1000 person- years of follow- up
Time frame
from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years)4
The incidence of all CDI (primary and recurrent)
Occurence of all C.difficile infection cases
Time frame
from 14 days after Vaccination 2 to the end of the surveillance period (up to approximately 3.5 years) Source ClinicalTrials.gov